First appearance:

The Mole

Mr. Bean hide mole in bottle in episode "The Mole"

In the episode "The Mole", he disturbs Mrs. Wicket and her friend in the garden so she asks Mr. Bean to get rid of it.

Bean's Bounty

In the episode Bean's Bounty, when Mr. Bean digging the artifact that has been detected by his metal detector and clean up the artifact covered by mud, the mole showing up from the soil and see Mr. Bean cleaning up the mud. When the mud suddenly uncover the artifact is actually a nuclear bomb, the mole scared and run away, cause Mr. Bean thinking his hammer got problem until he sees he actually digging a bomb.